The life of the leading racehorse, Conduit, was allegedly threatened this summer by a blackmailer who sought to prevent its participation in Ascot's premier race.

The menacing demands are said to have been sent by text message and email, threatening to kill the horse if it was not withdrawn from the King George VI and Queen Elizabeth Stakes in July. Conduit was then a short-priced favourite for that prestigious race, which he went on to win.

During the build-up to the Ascot race, discussions were held between Sir Michael Stoute, who trains Conduit in Newmarket, and the integrity department of the British Horseracing Authority to ensure the safety of the horse. The BHA laid on increased security during the horse's journey to Ascot and when he was stabled at the racecourse.

Peter Reynolds, the general manager of Ireland's Ballymacoll Stud, in whose ownership the horse runs, is said to have received the threats in the days prior to the race, staged on 25 July, and contacted the police.

An investigation followed, involving the co-operation of the Suffolk and Greater Manchester police forces. It resulted in the arrest and subsequent charging in August of Andrew Rodgerson, 26, of Rochdale, with one count of blackmail. He is due to appear at Bolton crown court on 1 December.

"This charge relates to an incident in which a racehorse owner received threats before a race at the end of July," said a spokesman for Greater Manchester police, who brought the case to charge.

Speaking from his County Meath base, Reynolds acknowledged receipt of the threats. "I can confirm that a threat was made to me and the matter was placed in the hands of the police," he said.

As the winner of last year's Breeders' Cup Turf in America, Conduit was already a valuable commodity as a future stallion prior to winning the King George. One bloodstock expert estimates his value at stud now to be about £5m.

Conduit went on to win the King George under Ryan Moore, the champion jockey, netting more than £500,000 in prize money. He beat his stable companions Tartan Bearer, also in the same ownership, and Ask in a clean sweep for Stoute, the nine-time champion trainer.